Simple CAN Node Reference Design
Created: Sep 03, 2014
No description available.
This design features a smart, low-cost and stand-alone Controller Area Network (CAN) node. It uses an 8-pin Microchip microcontroller, PIC12C672 and an 18-pin MCP2515 Microchip stand-alone CAN controller. The CAN node is capable of monitoring five external inputs with two analog and three digital. In addition, it is interrupt driven that automatically generate messages based on its values. This CAN node supports both "time-based" and "event driven" messages transmissions.
The system supports a maximum CAN bus speed of 125Kbits per second and both standard or extended frames. The system is presented using standard frames and some code changes would be required to implement extended frames. This application note focuses on the design and development of the node from the system level. No discussion of the nature of the analog signals is presented and the digital inputs are simply switch contacts, whose purpose is left for the reader to define. This design concentrates on the unique requirements of implementing the CAN node functions using an I/O limited microcontroller and a stand-alone CAN protocol controller.
A smart CAN node can be implemented with low-cost, low pin count devices, such as the PIC12C672 microcontroller and MCP2515 stand-alone CAN controller, providing a very flexible and effective solution for a variety of applications requiring robust communications at bit rates reaching 1Mbps. Incorporating the CAN protocol into your design is a low-cost, reliable way to function in a difficult electrical environment with a high degree of real-time capability.